Even if you're not registered as NHS Staff with Vodafone, the offer is still open to you and is available via the VeryMe rewards scheme in the My Vodafone app, so if you want to take advantage, make sure you have the app installed.
The company also said that it would be upgrading vulnerable customers to the same 30-day unlimited data offer for free, the idea being that they can keep in touch with their families using video calling apps without worrying about data use.
If you’re eligible for the latter offer, you will receive a text message about it.
Vodafone says it will make the offer available to more customers if it can. There’s also a six-month, half price offer on its 24-month SIM only unlimited plans.
Nick Jeffery, Vodafone’s CEO, said: “Our role in these difficult and worrying times is to keep the UK connected, even while we have to stay apart. We are offering 30 days of unlimited free data to our most vulnerable customers and the first 500,000 customers to sign up, to help ease any worries about running out of data or incurring additional charges.
"If our network capacity allows, we would love to be able to offer this to even more customers and will be monitoring the feasibility of this. In short, if we have more to give, we will. This is one of a series of measures that we are taking to help. We have already expanded our networks, given our customers free access to NHS online services and reduced the time it takes to pay small suppliers.”
If you're not eligible for this offer and you want more data, here are the best SIM-only unlimited data deals.